The invention relates to a railway switch for use in suspended railways of the type making use of two-runway-rail suspension track. The two runway rails which form the bearing track for the suspension rail are spaced apart to form a slit. The traveller has a plurality of traveller wheels, arranged one after the other. These traveller wheels are mid-flanged and having opposite axial end sections bearing upon respective ones of the two runway rails of the track, with the central flange riding in the slit intermediate the runway rails. Hangers extend from the traveller down through the slit and suspend a railway car, or the like. The traveller is provided with two linear motors, located to opposite sides of the traveller. Reaction rails, for example composed of a series of reaction bars, extend alongside the track and cooperate with the linear motors to cause the traveller to advance along the track. When the traveller comes to a switching region, one of the linear motors is deenergized so that the other will effect not only advancement of the traveller but will furthermore cause the traveller to be steered onto the selected branch of the switch. Above the level of the linear motors, the traveller is provided with horizontally spaced guide rollers rotatable about respective vertical axes. These guide rollers bear upon guide rails located at the level of the guide rollers and extending alongside the track. In the switching region there are provided steering rails which extend alongside the outer rails of the branch sections. The traveller is provided with a steering structure capable of engaging a selected one of the steering rails to effect steering by purely mechanical means, in the event of a partial or complete electrical power loss of the linear motor which would normally effect the steering action. Uptrack and down-track of the switching region, the reaction rails, the guide rails, and to their limited extent the steering rails are horizontally spaced from the respective track centerline by constant respective distances.
German published Pat. application DT-OS 2 164 078 discloses a structure for the suspension rail of a suspended railway. The suspension rail is mounted on supports and has a box-like cross-sectional profile encasing the traveller. The suspension rail is slotted at its bottom wall for the passage of the hangers which extend down from the traveller to support the suspended railway car. The travellers of the railway are provided with mid-flanged traveller wheels which ride down the middle of the two-runway-rail track. If the suspended railway cars follow each other closely and are to be routed onto different branches of a switch, then it is desirable to provide a switch which effects steering of the railway cars onto the selected branches without the need for moving parts such as switch blades, and the like. However, if conventional switch blades and the like are to be eliminated, there arises the problem of how to reliably effect the routing of the cars onto the different branches of the switch.
German published Pat. application DT-OS 2 215 807 proposes a solution to this problem. In the switching region, the suspension rail is provided with magnets located at the outer sides of the respective outer rails of the branch sections of the switch. The traveller is provided on its opposite sides with armature plates which can be selectively activated to move into the region of the magnetic field of the left-branch magnets or into the region of the magnetic field of the right-branch magnets. When the railway car approaches the switching region, one or the other of the armature plates is activated, with the result that the traveller of the railway car is caused to follow either the outer runway rail of the left branch or else the outer runway rail of the right branch, and in this way steering of the railway car is effected. In this publication, there is also disclosed the concept of providing steering rails alongside the steering magnets. The traveller is provided with a steering structure capable of hooking behind the steering rail of one of the other branch section, so that steering by purely mechanical means will occur in the event of a loss of the magnetic steering action, due to a partial or complete electric power loss. However, this known construction has a considerable disadvantage.
The central slit defined intermediate the two runway rails of the suspension railroad track spreads apart in the switching region to form a large empty space or switching gap. If for example the railway car is travelling on the stem section of the switch and is to be steered onto the right branch section, then, as the traveller of the railway car crosses the switching gap, the left traveller wheel sections will cross the gap unsupported from below. Because of the horizontal spacing, as considered in transverse cross-section, between the right-hand or load-bearing runway rail in this example, on the one hand, and, on the other hand, the center of gravity of the traveller and the suspended railway car, the traveller will tend to tilt to the left when crossing the switching gap, in passing from the stem section of the switch to the right branch section.
This tendency to tilt to the left is opposed by the attractive force of the aforementioned steering magnets running alongside the outer runway rail of the right branch section. However, as indicated above, in the event of a partial or complete power loss resulting in deenergization of the steering magnets, the steering becomes purely mechanical, with the hooked ends of a steering structure on the traveller hooking behind the steering rail which runs alongside the outer runway rail of the right branch section along the switching region. However, this latter steering action, which comes into play only in the event of the power loss, results in a limited tilting of the traveller to the left, due to the play between the right steering structure and the right steering rail. The presence of this play is appropriate, since it prevents the mechanical steering engagement from occurring except when the attractive steering force of the steering magnets fails. However, the problem produced by this action is that the unsupported left traveller wheel sections may assume a level below the level of the upper or bearing surface of the left runway rail of the right branch section, in this example, with the result that the unsupported left traveller wheel sections, instead of smoothly engaging the inner runway of the branch section after crossing the switch gap, instead collide with it.
German published patent application DT-OS 2 328 366 discloses another such suspended railroad suspension rail construction. There, the steering of the traveller, which is provided with a mid-flanged traveller wheel which rides down the center of the track defined by the two spaced runway rails, is effected by the separate control of linear motors located at opposite sides of the traveller and cooperating with respective reaction rails extending along opposite sides of the two-runway-rail track. Normally, both linear motors are energized, for effecting advancement of the traveller. When the traveller enters a switching region, one linear motor is deenergized, so that the linear motor which remains energized not only effects advancement, but furthermore causes the traveller to be attracted to the associated reaction rail. To stabilize the traveller against lateral tilting and swinging, there are provided at the top of the traveller guide rollers bearing upon lateral guide rails running along opposite sides of the track. When passing through the switch, the traveller wheel section associated with the deenergized linear motor is unsupported, resulting in the aforedescribed tendency of the traveller to tilt to the unsupported side. To counteract this tendency to tilt, the linear motor which remains energized is energized to a considerably greater extent than when both linear motors are energized simultaneously The energization of the linear motor which remains energized to effect both advancement and tilting must be increased for still another reason. Specifically, one of the two branch sections of the suspension railway switch is a curved branch section, and accordingly the magnetic coupling between the linear motor and the reaction bars of the associated reaction rail is somewhat decreased if the traveller is passing along this curve. To compensate for this decrease, the energization of the linear motor which effects the steering must be still further increased. It is considered quite undesirable that as the traveller enters the switching region the energization of the linear motor which is called upon to effect the steering action must be increased so greatly and so relatively suddenly.